Transistors can be divided into bipolar transistors and field effect transistors. According to different uses, transistors can be divided into power transistors, microwave transistors and low-noise transistors.
In addition to general transistors used for amplification, oscillation, and switching, there are also some special purpose transistors, such as phototransistors, magneto-sensitive transistors, and field effect sensors.
These devices can not only convert the information of some environmental factors into electrical signals, but also have the amplification effect of general transistors to obtain larger output signals. In addition, there are some special devices, such as unijunction transistors can be used to generate sawtooth waves, thyristors can be used in various high-current control circuits, and charge-coupled devices can be used as imaging devices or information storage devices.
In military equipment such as communications and radar, high-sensitivity, low-noise semiconductor receivers are mainly used to receive weak signals. With the rapid development of microwave communication technology, microwave semi-conducting low-noise devices have developed rapidly, with increasing operating frequencies and decreasing noise figures. Microwave semiconductor devices have been widely used in air defense, antimissile and electronic warfare systems due to their excellent performance, small size, light weight and low power consumption.
